314 results on '"Lee, Youjin"'
Search Results
2. Time-of-flight detection of terahertz phonon-polariton
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Luo, Tianchuang, Ilyas, Batyr, Hoegen, A. von, Lee, Youjin, Park, Jaena, Park, Je-Geun, and Gedik, Nuh
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- 2024
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3. Amygdala electrical stimulation for operant conditioning in rat navigation
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Lee, Youjin, Kim, Soonyoung, Cho, Yoon Kyung, Kong, Chanho, Chang, Jin Woo, and Jun, Sang Beom
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- 2024
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4. Early lysosome defects precede neurodegeneration with amyloid-β and tau aggregation in NHE6-null rat brain.
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Lee, YouJin, Miller, Morgan R, Fernandez, Marty A, Berg, Elizabeth L, Prada, Adriana M, Ouyang, Qing, Schmidt, Michael, Silverman, Jill L, Young-Pearse, Tracy L, and Morrow, Eric M
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Alzheimer's Disease including Alzheimer's Disease Related Dementias (AD/ADRD) ,Acquired Cognitive Impairment ,Brain Disorders ,Alzheimer's Disease ,Neurosciences ,Neurodegenerative ,Rare Diseases ,Aging ,Dementia ,2.1 Biological and endogenous factors ,Aetiology ,Neurological ,Alzheimer Disease ,Amyloid beta-Peptides ,Animals ,Ataxia ,Brain ,Disease Models ,Animal ,Epilepsy ,Genetic Diseases ,X-Linked ,Hippocampus ,Intellectual Disability ,Lysosomes ,Male ,Microcephaly ,Ocular Motility Disorders ,Rats ,Sodium-Hydrogen Exchangers ,tau Proteins ,rat model ,lysosomes ,neurodegeneration ,tau ,amyloid beta ,Medical and Health Sciences ,Psychology and Cognitive Sciences ,Neurology & Neurosurgery - Abstract
Loss-of-function mutations in the X-linked endosomal Na+/H+ exchanger 6 (NHE6) cause Christianson syndrome in males. Christianson syndrome involves endosome dysfunction leading to early cerebellar degeneration, as well as later-onset cortical and subcortical neurodegeneration, potentially including tau deposition as reported in post-mortem studies. In addition, there is reported evidence of modulation of amyloid-β levels in experimental models wherein NHE6 expression was targeted. We have recently shown that loss of NHE6 causes defects in endosome maturation and trafficking underlying lysosome deficiency in primary mouse neurons in vitro. For in vivo studies, rat models may have an advantage over mouse models for the study of neurodegeneration, as rat brain can demonstrate robust deposition of endogenously-expressed amyloid-β and tau in certain pathological states. Mouse models generally do not show the accumulation of insoluble, endogenously-expressed (non-transgenic) tau or amyloid-β. Therefore, to study neurodegeneration in Christianson syndrome and the possibility of amyloid-β and tau pathology, we generated an NHE6-null rat model of Christianson syndrome using CRISPR-Cas9 genome-editing. Here, we present the sequence of pathogenic events in neurodegenerating NHE6-null male rat brains across the lifespan. NHE6-null rats demonstrated an early and rapid loss of Purkinje cells in the cerebellum, as well as a more protracted neurodegenerative course in the cerebrum. In both the cerebellum and cerebrum, lysosome deficiency is an early pathogenic event, preceding autophagic dysfunction. Microglial and astrocyte activation also occur early. In the hippocampus and cortex, lysosome defects precede loss of pyramidal cells. Importantly, we subsequently observed biochemical and in situ evidence of both amyloid-β and tau aggregation in the aged NHE6-null hippocampus and cortex (but not in the cerebellum). Tau deposition is widely distributed, including cortical and subcortical distributions. Interestingly, we observed tau deposition in both neurons and glia, as has been reported in Christianson syndrome post-mortem studies previously. In summary, this experimental model is among very few examples of a genetically modified animal that exhibits neurodegeneration with deposition of endogenously-expressed amyloid-β and tau. This NHE6-null rat will serve as a new robust model for Christianson syndrome. Furthermore, these studies provide evidence for linkages between endolysosome dysfunction and neurodegeneration involving protein aggregations, including amyloid-β and tau. Therefore these studies may provide insight into mechanisms of more common neurodegenerative disorders, including Alzheimer's disease and related dementias.
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- 2022
5. Association of nightmares with cardio-cerebrovascular disease, hypertension and hyperlipidemia in older adults: A population-based cross-sectional study
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Lee, Youjin, Park, Dasom, Kim, Soriul, Shin, Chol, and Suh, Sooyeon
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- 2024
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6. Distinguishing nontuberculous mycobacterial lung disease and Mycobacterium tuberculosis lung disease on X-ray images using deep transfer learning
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Park, Minwoo, Lee, Youjin, Kim, Sangil, Kim, Young-Jin, Kim, Shin Young, Kim, Yeongsic, and Kim, Hyun-Min
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- 2023
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7. Ultraviolet light scattering by a silicon Bethe hole
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Lee Dukhyung, Lee Youjin, and Kim Dai-Sik
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scattering ,bethe hole ,magnetic dipole ,uv plasmonics ,silicon ,Physics ,QC1-999 - Abstract
Bethe’s theory predicts that scattering by a small hole on a thin perfect electric conductor (PEC) is presented as radiation by an in-plane magnetic dipole of the incident magnetic field direction. Even in the near-infrared range where metals are no more PEC, the magnetic dipole radiation of Bethe holes has been demonstrated. However, such Bethe holes’ nature has not been addressed yet in the ultraviolet (UV) range where conductivity of metals becomes severely deteriorated. Meanwhile, UV plasmonics has been elevating its importance in spectroscopy and photochemistry, recognizing silicon (Si) as an alternative plasmonic metal featuring the interband transition in the UV range. In this work, we expanded the Bethe’s theory’s prediction to the UV range by investigating Si Bethe holes theoretically and experimentally in terms of the scattering pattern and polarization. Simulation results showed that the scattered field distribution resembles that of an in-plane magnetic dipole, and the dipole direction at oblique incidence is roughly given as the incident magnetic field direction with a deviation angle which can be predicted from the Fresnel equations. Simulation with various diameters showed that the magnetic dipole nature maintains with a diameter less than the quarter-wavelength and multipoles becomes noticeable for diameters larger than the half-wavelength. We performed scattering polarization measurement at 69-degree incidence, which confirms the theoretical analysis. The features of Si Bethe holes demonstrated here will be useful for designing UV plasmonic metasurfaces.
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- 2023
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8. Efficient generation of isogenic primary human myeloid cells using CRISPR-Cas9 ribonucleoproteins
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Hiatt, Joseph, Cavero, Devin A, McGregor, Michael J, Zheng, Weihao, Budzik, Jonathan M, Roth, Theodore L, Haas, Kelsey M, Wu, David, Rathore, Ujjwal, Meyer-Franke, Anke, Bouzidi, Mohamed S, Shifrut, Eric, Lee, Youjin, Kumar, Vigneshwari Easwar, Dang, Eric V, Gordon, David E, Wojcechowskyj, Jason A, Hultquist, Judd F, Fontaine, Krystal A, Pillai, Satish K, Cox, Jeffery S, Ernst, Joel D, Krogan, Nevan J, and Marson, Alexander
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Biological Sciences ,Biotechnology ,Genetics ,Infectious Diseases ,Stem Cell Research ,2.1 Biological and endogenous factors ,Aetiology ,Animals ,CRISPR-Cas Systems ,Genome ,Humans ,Mice ,Myeloid Cells ,Ribonucleoproteins ,CRISPR ,Cas9 ,dendritic cells ,electroporation ,host-pathogen interactions ,knockout ,macrophages ,monocytes ,myeloid cells ,ribonculeoproteins ,Biochemistry and Cell Biology ,Medical Physiology ,Biological sciences - Abstract
Genome engineering of primary human cells with CRISPR-Cas9 has revolutionized experimental and therapeutic approaches to cell biology, but human myeloid-lineage cells have remained largely genetically intractable. We present a method for the delivery of CRISPR-Cas9 ribonucleoprotein (RNP) complexes by nucleofection directly into CD14+ human monocytes purified from peripheral blood, leading to high rates of precise gene knockout. These cells can be efficiently differentiated into monocyte-derived macrophages or dendritic cells. This process yields genetically edited cells that retain transcript and protein markers of myeloid differentiation and phagocytic function. Genetic ablation of the restriction factor SAMHD1 increased HIV-1 infection >50-fold, demonstrating the power of this system for genotype-phenotype interrogation. This fast, flexible, and scalable platform can be used for genetic studies of human myeloid cells in immune signaling, inflammation, cancer immunology, host-pathogen interactions, and beyond, and could facilitate the development of myeloid cellular therapies.
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- 2021
9. XYZeq: Spatially resolved single-cell RNA sequencing reveals expression heterogeneity in the tumor microenvironment
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Lee, Youjin, Bogdanoff, Derek, Wang, Yutong, Hartoularos, George C, Woo, Jonathan M, Mowery, Cody T, Nisonoff, Hunter M, Lee, David S, Sun, Yang, Lee, James, Mehdizadeh, Sadaf, Cantlon, Joshua, Shifrut, Eric, Ngyuen, David N, Roth, Theodore L, Song, Yun S, Marson, Alexander, Chow, Eric D, and Ye, Chun Jimmie
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Biological Sciences ,Bioinformatics and Computational Biology ,Regenerative Medicine ,Stem Cell Research ,Biotechnology ,Genetics ,Stem Cell Research - Nonembryonic - Non-Human ,Cancer ,Human Genome ,Underpinning research ,1.1 Normal biological development and functioning ,Generic health relevance ,Animals ,Gene Expression Profiling ,Mice ,Neoplasms ,Sequence Analysis ,RNA ,Single-Cell Analysis ,Transcriptome ,Tumor Microenvironment ,Exome Sequencing - Abstract
Single-cell RNA sequencing (scRNA-seq) of tissues has revealed remarkable heterogeneity of cell types and states but does not provide information on the spatial organization of cells. To better understand how individual cells function within an anatomical space, we developed XYZeq, a workflow that encodes spatial metadata into scRNA-seq libraries. We used XYZeq to profile mouse tumor models to capture spatially barcoded transcriptomes from tens of thousands of cells. Analyses of these data revealed the spatial distribution of distinct cell types and a cell migration-associated transcriptomic program in tumor-associated mesenchymal stem cells (MSCs). Furthermore, we identify localized expression of tumor suppressor genes by MSCs that vary with proximity to the tumor core. We demonstrate that XYZeq can be used to map the transcriptome and spatial localization of individual cells in situ to reveal how cell composition and cell states can be affected by location within complex pathological tissue.
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- 2021
10. Somatosensory ECoG-based brain–machine interface with electrical stimulation on medial forebrain bundle
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Cho, Yoon Kyung, Koh, Chin Su, Lee, Youjin, Park, Minkyung, Kim, Tae Jun, Jung, Hyun Ho, Chang, Jin Woo, and Jun, Sang Beom
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- 2023
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11. Evaluation of SARS-CoV-2 serology assays reveals a range of test performance
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Whitman, Jeffrey D, Hiatt, Joseph, Mowery, Cody T, Shy, Brian R, Yu, Ruby, Yamamoto, Tori N, Rathore, Ujjwal, Goldgof, Gregory M, Whitty, Caroline, Woo, Jonathan M, Gallman, Antonia E, Miller, Tyler E, Levine, Andrew G, Nguyen, David N, Bapat, Sagar P, Balcerek, Joanna, Bylsma, Sophia A, Lyons, Ana M, Li, Stacy, Wong, Allison Wai-yi, Gillis-Buck, Eva Mae, Steinhart, Zachary B, Lee, Youjin, Apathy, Ryan, Lipke, Mitchell J, Smith, Jennifer Anne, Zheng, Tina, Boothby, Ian C, Isaza, Erin, Chan, Jackie, Acenas, Dante D, Lee, Jinwoo, Macrae, Trisha A, Kyaw, Than S, Wu, David, Ng, Dianna L, Gu, Wei, York, Vanessa A, Eskandarian, Haig Alexander, Callaway, Perri C, Warrier, Lakshmi, Moreno, Mary E, Levan, Justine, Torres, Leonel, Farrington, Lila A, Loudermilk, Rita P, Koshal, Kanishka, Zorn, Kelsey C, Garcia-Beltran, Wilfredo F, Yang, Diane, Astudillo, Michael G, Bernstein, Bradley E, Gelfand, Jeffrey A, Ryan, Edward T, Charles, Richelle C, Iafrate, A John, Lennerz, Jochen K, Miller, Steve, Chiu, Charles Y, Stramer, Susan L, Wilson, Michael R, Manglik, Aashish, Ye, Chun Jimmie, Krogan, Nevan J, Anderson, Mark S, Cyster, Jason G, Ernst, Joel D, Wu, Alan HB, Lynch, Kara L, Bern, Caryn, Hsu, Patrick D, and Marson, Alexander
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Biological Sciences ,Biomedical and Clinical Sciences ,Clinical Sciences ,Biodefense ,Pneumonia & Influenza ,Prevention ,Clinical Research ,Infectious Diseases ,Lung ,Vaccine Related ,Pneumonia ,Emerging Infectious Diseases ,Detection ,screening and diagnosis ,4.1 Discovery and preclinical testing of markers and technologies ,4.2 Evaluation of markers and technologies ,Infection ,Good Health and Well Being ,Adult ,Aged ,Aged ,80 and over ,Antibodies ,Viral ,Betacoronavirus ,Biotechnology ,COVID-19 ,COVID-19 Testing ,Chromatography ,Affinity ,Clinical Laboratory Techniques ,Coronavirus Infections ,Enzyme-Linked Immunosorbent Assay ,Female ,Humans ,Immunoglobulin G ,Immunoglobulin M ,Male ,Middle Aged ,Pandemics ,Pneumonia ,Viral ,Point-of-Care Testing ,Reverse Transcriptase Polymerase Chain Reaction ,SARS-CoV-2 ,Sensitivity and Specificity ,Young Adult - Abstract
Appropriate use and interpretation of serological tests for assessments of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure, infection and potential immunity require accurate data on assay performance. We conducted a head-to-head evaluation of ten point-of-care-style lateral flow assays (LFAs) and two laboratory-based enzyme-linked immunosorbent assays to detect anti-SARS-CoV-2 IgM and IgG antibodies in 5-d time intervals from symptom onset and studied the specificity of each assay in pre-coronavirus disease 2019 specimens. The percent of seropositive individuals increased with time, peaking in the latest time interval tested (>20 d after symptom onset). Test specificity ranged from 84.3% to 100.0% and was predominantly affected by variability in IgM results. LFA specificity could be increased by considering weak bands as negative, but this decreased detection of antibodies (sensitivity) in a subset of SARS-CoV-2 real-time PCR-positive cases. Our results underline the importance of seropositivity threshold determination and reader training for reliable LFA deployment. Although there was no standout serological assay, four tests achieved more than 80% positivity at later time points tested and more than 95% specificity.
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- 2020
12. Test performance evaluation of SARS-CoV-2 serological assays
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Whitman, Jeffrey D, Hiatt, Joseph, Mowery, Cody T, Shy, Brian R, Yu, Ruby, Yamamoto, Tori N, Rathore, Ujjwal, Goldgof, Gregory M, Whitty, Caroline, Woo, Jonathan M, Gallman, Antonia E, Miller, Tyler E, Levine, Andrew G, Nguyen, David N, Bapat, Sagar P, Balcerek, Joanna, Bylsma, Sophia A, Lyons, Ana M, Li, Stacy, Wong, Allison Wai-yi, Gillis-Buck, Eva Mae, Steinhart, Zachary B, Lee, Youjin, Apathy, Ryan, Lipke, Mitchell J, Smith, Jennifer Anne, Zheng, Tina, Boothby, Ian C, Isaza, Erin, Chan, Jackie, Acenas, Dante D, Lee, Jinwoo, Macrae, Trisha A, Kyaw, Than S, Wu, David, Ng, Dianna L, Gu, Wei, York, Vanessa A, Eskandarian, Haig Alexander, Callaway, Perri C, Warrier, Lakshmi, Moreno, Mary E, Levan, Justine, Torres, Leonel, Farrington, Lila A, Loudermilk, Rita, Koshal, Kanishka, Zorn, Kelsey C, Garcia-Beltran, Wilfredo F, Yang, Diane, Astudillo, Michael G, Bernstein, Bradley E, Gelfand, Jeffrey A, Ryan, Edward T, Charles, Richelle C, Iafrate, A John, Lennerz, Jochen K, Miller, Steve, Chiu, Charles Y, Stramer, Susan L, Wilson, Michael R, Manglik, Aashish, Ye, Chun Jimmie, Krogan, Nevan J, Anderson, Mark S, Cyster, Jason G, Ernst, Joel D, Wu, Alan HB, Lynch, Kara L, Bern, Caryn, Hsu, Patrick D, and Marson, Alexander
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Infectious Diseases ,Vaccine Related ,Clinical Research ,Pneumonia ,Lung ,Pneumonia & Influenza ,Biodefense ,Prevention ,Emerging Infectious Diseases ,Detection ,screening and diagnosis ,4.2 Evaluation of markers and technologies ,Infection ,Good Health and Well Being - Abstract
Background:Serological tests are crucial tools for assessments of SARS-CoV-2 exposure, infection and potential immunity. Their appropriate use and interpretation require accurate assay performance data. Method:We conducted an evaluation of 10 lateral flow assays (LFAs) and two ELISAs to detect anti-SARS-CoV-2 antibodies. The specimen set comprised 128 plasma or serum samples from 79 symptomatic SARS-CoV-2 RT-PCR-positive individuals; 108 pre-COVID-19 negative controls; and 52 recent samples from individuals who underwent respiratory viral testing but were not diagnosed with Coronavirus Disease 2019 (COVID-19). Samples were blinded and LFA results were interpreted by two independent readers, using a standardized intensity scoring system. Results:Among specimens from SARS-CoV-2 RT-PCR-positive individuals, the percent seropositive increased with time interval, peaking at 81.8-100.0% in samples taken >20 days after symptom onset. Test specificity ranged from 84.3-100.0% in pre-COVID-19 specimens. Specificity was higher when weak LFA bands were considered negative, but this decreased sensitivity. IgM detection was more variable than IgG, and detection was highest when IgM and IgG results were combined. Agreement between ELISAs and LFAs ranged from 75.7-94.8%. No consistent cross-reactivity was observed. Conclusion:Our evaluation showed heterogeneous assay performance. Reader training is key to reliable LFA performance, and can be tailored for survey goals. Informed use of serology will require evaluations covering the full spectrum of SARS-CoV-2 infections, from asymptomatic and mild infection to severe disease, and later convalescence. Well-designed studies to elucidate the mechanisms and serological correlates of protective immunity will be crucial to guide rational clinical and public health policies.
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- 2020
13. Pooled Knockin Targeting for Genome Engineering of Cellular Immunotherapies
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Roth, Theodore L, Li, P Jonathan, Blaeschke, Franziska, Nies, Jasper F, Apathy, Ryan, Mowery, Cody, Yu, Ruby, Nguyen, Michelle LT, Lee, Youjin, Truong, Anna, Hiatt, Joseph, Wu, David, Nguyen, David N, Goodman, Daniel, Bluestone, Jeffrey A, Ye, Chun Jimmie, Roybal, Kole, Shifrut, Eric, and Marson, Alexander
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Biomedical and Clinical Sciences ,Oncology and Carcinogenesis ,Immunology ,Biotechnology ,Human Genome ,Immunization ,Genetics ,Gene Therapy ,Vaccine Related ,Cancer ,5.2 Cellular and gene therapies ,Underpinning research ,Development of treatments and therapeutic interventions ,1.1 Normal biological development and functioning ,Animals ,Blood Cells ,CRISPR-Cas Systems ,Clustered Regularly Interspaced Short Palindromic Repeats ,Gene Knock-In Techniques ,Genetic Engineering ,Humans ,Immunotherapy ,Mice ,Mice ,Inbred NOD ,Mice ,SCID ,RNA ,Guide ,Kinetoplastida ,Single-Cell Analysis ,T-Lymphocytes ,Transcriptome ,CRISPR ,cell therapy ,human T cell ,knockins ,pooled screen ,single-cell RNA-seq ,Biological Sciences ,Medical and Health Sciences ,Developmental Biology ,Biological sciences ,Biomedical and clinical sciences - Abstract
Adoptive transfer of genetically modified immune cells holds great promise for cancer immunotherapy. CRISPR knockin targeting can improve cell therapies, but more high-throughput methods are needed to test which knockin gene constructs most potently enhance primary cell functions in vivo. We developed a widely adaptable technology to barcode and track targeted integrations of large non-viral DNA templates and applied it to perform pooled knockin screens in primary human T cells. Pooled knockin of dozens of unique barcoded templates into the T cell receptor (TCR)-locus revealed gene constructs that enhanced fitness in vitro and in vivo. We further developed pooled knockin sequencing (PoKI-seq), combining single-cell transcriptome analysis and pooled knockin screening to measure cell abundance and cell state ex vivo and in vivo. This platform nominated a novel transforming growth factor β (TGF-β) R2-41BB chimeric receptor that improved solid tumor clearance. Pooled knockin screening enables parallelized re-writing of endogenous genetic sequences to accelerate discovery of knockin programs for cell therapies.
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- 2020
14. Quality improvement of outpatient clinical chemistry tests through a novel middleware-laboratory information system solution
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Park, Minwoo, Kim, Young-Jin, Jung, Dawoon, Kim, Yeongsic, Kim, Hyun-Min, Lee, Youjin, and Choi, In Young
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- 2023
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15. A large CRISPR-induced bystander mutation causes immune dysregulation.
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Simeonov, Dimitre R, Brandt, Alexander J, Chan, Alice Y, Cortez, Jessica T, Li, Zhongmei, Woo, Jonathan M, Lee, Youjin, Carvalho, Claudia MB, Indart, Alyssa C, Roth, Theodore L, Zou, James, May, Andrew P, Lupski, James R, Anderson, Mark S, Buaas, F William, Rokhsar, Daniel S, and Marson, Alexander
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T-Lymphocytes ,Cells ,Cultured ,Animals ,Mice ,Inbred NOD ,DNA Damage ,DNA Repair ,Gene Expression Regulation ,Gene Duplication ,Base Sequence ,Mutation ,T-Lymphocytes ,Regulatory ,Interleukin-2 Receptor alpha Subunit ,CRISPR-Cas Systems ,Gene Editing ,Cells ,Cultured ,Mice ,Inbred NOD ,Regulatory - Abstract
A persistent concern with CRISPR-Cas9 gene editing has been the potential to generate mutations at off-target genomic sites. While CRISPR-engineering mice to delete a ~360 bp intronic enhancer, here we discovered a founder line that had marked immune dysregulation caused by a 24 kb tandem duplication of the sequence adjacent to the on-target deletion. Our results suggest unintended repair of on-target genomic cuts can cause pathogenic "bystander" mutations that escape detection by routine targeted genotyping assays.
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- 2019
16. Syngas production for Fischer-Tropsch process via co-electrolytic processes of CO2 reduction and NH3 oxidation
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Choi, Minjun, Kim, Jin Won, Chung, Sunki, Lee, Youjin, Bong, Sungyool, and Lee, Jaeyoung
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- 2022
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17. Discovery of stimulation-responsive immune enhancers with CRISPR activation
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Simeonov, Dimitre R, Gowen, Benjamin G, Boontanrart, Mandy, Roth, Theodore L, Gagnon, John D, Mumbach, Maxwell R, Satpathy, Ansuman T, Lee, Youjin, Bray, Nicolas L, Chan, Alice Y, Lituiev, Dmytro S, Nguyen, Michelle L, Gate, Rachel E, Subramaniam, Meena, Li, Zhongmei, Woo, Jonathan M, Mitros, Therese, Ray, Graham J, Curie, Gemma L, Naddaf, Nicki, Chu, Julia S, Ma, Hong, Boyer, Eric, Van Gool, Frederic, Huang, Hailiang, Liu, Ruize, Tobin, Victoria R, Schumann, Kathrin, Daly, Mark J, Farh, Kyle K, Ansel, K Mark, Ye, Chun J, Greenleaf, William J, Anderson, Mark S, Bluestone, Jeffrey A, Chang, Howard Y, Corn, Jacob E, and Marson, Alexander
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Biological Sciences ,Biomedical and Clinical Sciences ,Immunology ,Human Genome ,Genetics ,Autoimmune Disease ,Animals ,Antigens ,CD ,Antigens ,Differentiation ,T-Lymphocyte ,Autoimmunity ,CRISPR-Cas Systems ,Cell Differentiation ,Cell Line ,Chromatin ,Clustered Regularly Interspaced Short Palindromic Repeats ,Enhancer Elements ,Genetic ,Female ,Gene Expression Regulation ,Humans ,Interleukin-2 Receptor alpha Subunit ,Lectins ,C-Type ,Mice ,Receptors ,Antigen ,T-Cell ,Th17 Cells ,General Science & Technology - Abstract
The majority of genetic variants associated with common human diseases map to enhancers, non-coding elements that shape cell-type-specific transcriptional programs and responses to extracellular cues. Systematic mapping of functional enhancers and their biological contexts is required to understand the mechanisms by which variation in non-coding genetic sequences contributes to disease. Functional enhancers can be mapped by genomic sequence disruption, but this approach is limited to the subset of enhancers that are necessary in the particular cellular context being studied. We hypothesized that recruitment of a strong transcriptional activator to an enhancer would be sufficient to drive target gene expression, even if that enhancer was not currently active in the assayed cells. Here we describe a discovery platform that can identify stimulus-responsive enhancers for a target gene independent of stimulus exposure. We used tiled CRISPR activation (CRISPRa) to synthetically recruit a transcriptional activator to sites across large genomic regions (more than 100 kilobases) surrounding two key autoimmunity risk loci, CD69 and IL2RA. We identified several CRISPRa-responsive elements with chromatin features of stimulus-responsive enhancers, including an IL2RA enhancer that harbours an autoimmunity risk variant. Using engineered mouse models, we found that sequence perturbation of the disease-associated Il2ra enhancer did not entirely block Il2ra expression, but rather delayed the timing of gene activation in response to specific extracellular signals. Enhancer deletion skewed polarization of naive T cells towards a pro-inflammatory T helper (TH17) cell state and away from a regulatory T cell state. This integrated approach identifies functional enhancers and reveals how non-coding variation associated with human immune dysfunction alters context-specific gene programs.
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- 2017
18. Temperature-Dependent Hole Transfer from Photoexcited Quantum Dots to Molecular Species: Evidence for Trap-Mediated Transfer
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Olshansky, Jacob H, Balan, Arunima D, Ding, Tina X, Fu, Xiao, Lee, Youjin V, and Alivisatos, A Paul
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Engineering ,Nanotechnology ,quantum dots ,charge transfer ,cadmium selenide ,hole traps ,temperature dependence ,ferrocene ,Nanoscience & Nanotechnology - Abstract
The effect of temperature on the rate of hole transfer from photoexcited quantum dots (QDs) is investigated by measuring the driving force dependence of the charge transfer rate for different sized QDs across a range of temperatures from 78 to 300 K. Spherical CdSe/CdS core/shell QDs were used with a series of ferrocene-derived molecular hole acceptors with an 800 meV range in electrochemical potential. Time-resolved photoluminescence measurements and photoluminescence quantum yield measurements in an integrating sphere were both performed from 78 to 300 K to obtain temperature-dependent rates for a series of driving forces as dictated by the nature of the molecular acceptor. For both QD sizes studied and all ligands, the Arrhenius plot of hole transfer exhibited an activated (linear) regime at higher temperatures and a temperature-independent regime at low temperatures. The extracted activation energies in the high-temperature regime were consistent across all ligands for a given QD size. This observation is not consistent with direct charge transfer from the QD valence band to the ferrocene acceptor. Instead, a model in which charge transfer is mediated by a shallow and reversible trap more accurately fits the experimental results. Implications for this observed trap-mediated transfer are discussed including as a strategy to more efficiently extract charge from QDs.
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- 2017
19. Effect of Thermal Fluctuations on the Radiative Rate in Core/Shell Quantum Dots
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Balan, Arunima D, Eshet, Hagai, Olshansky, Jacob H, Lee, Youjin V, Rabani, Eran, and Alivisatos, A Paul
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Chemical Sciences ,Physical Chemistry ,Engineering ,Physical Sciences ,Nanotechnology ,Core/shell quantum dots ,temperature-dependent lifetime ,exciton dynamics ,electronic structure ,Nanoscience & Nanotechnology - Abstract
The effect of lattice fluctuations and electronic excitations on the radiative rate is demonstrated in CdSe/CdS core/shell spherical quantum dots (QDs). Using a combination of time-resolved photoluminescence spectroscopy and atomistic simulations, we show that lattice fluctuations can change the radiative rate over the temperature range from 78 to 300 K. We posit that the presence of the core/shell interface plays a significant role in dictating this behavior. We show that the other major factor that underpins the change in radiative rate with temperature is the presence of higher energy states corresponding to electron excitation into the shell. These effects should be present in other core/shell samples and should also affect other excited state rates, such as the rate of Auger recombination or the rate of charge transfer.
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- 2017
20. Prognostic score‐based methods for estimating center effects based on survival probability: Application to post‐kidney transplant survival.
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Lee, Youjin, Reese, Peter P., Tran, Amelia H., and Schaubel, Douglas E.
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KIDNEY transplantation , *SURVIVAL rate , *GRAFT survival , *PROBABILITY theory - Abstract
In evaluating the performance of different facilities or centers on survival outcomes, the standardized mortality ratio (SMR), which compares the observed to expected mortality has been widely used, particularly in the evaluation of kidney transplant centers. Despite its utility, the SMR may exaggerate center effects in settings where survival probability is relatively high. An example is one‐year graft survival among U.S. kidney transplant recipients. We propose a novel approach to estimate center effects in terms of differences in survival probability (ie, each center versus a reference population). An essential component of the method is a prognostic score weighting technique, which permits accurately evaluating centers without necessarily specifying a correct survival model. Advantages of our approach over existing facility‐profiling methods include a metric based on survival probability (greater clinical relevance than ratios of counts/rates); direct standardization (valid to compare between centers, unlike indirect standardization based methods, such as the SMR); and less reliance on correct model specification (since the assumed model is used to generate risk classes as opposed to fitted‐value based 'expected' counts). We establish the asymptotic properties of the proposed weighted estimator and evaluate its finite‐sample performance under a diverse set of simulation settings. The method is then applied to evaluate U.S. kidney transplant centers with respect to graft survival probability. [ABSTRACT FROM AUTHOR]
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- 2024
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21. Conversion of Layered WS2 Crystals into Mixed‐Domain Electrochemical Catalysts by Plasma‐Assisted Surface Reconstruction.
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Park, Jiheon, Cho, Iaan, Jeon, Hotae, Lee, Youjin, Zhang, Jian, Lee, Dongwook, Cho, Min Kyung, Preston, Daniel J., Shong, Bonggeun, Kim, In Soo, and Lee, Won‐Kyu
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- 2024
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22. Joint modelling of competing risks and current status data : an application to a spontaneous labour study
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Lee, Youjin, Wang, Mei-Cheng, Grantz, Katherine L., and Sundaram, Rajeshwari
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- 2019
23. Hole Transfer from Photoexcited Quantum Dots: The Relationship between Driving Force and Rate
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Olshansky, Jacob H., Ding, Tina X., Lee, Youjin V., Leone, Stephen R., and Alivisatos, A. Paul
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- 2015
24. CRISPR screen in regulatory T cells reveals modulators of Foxp3
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Cortez, Jessica T., Montauti, Elena, Shifrut, Eric, Gatchalian, Jovylyn, Zhang, Yusi, Shaked, Oren, Xu, Yuanming, Roth, Theodore L., Simeonov, Dimitre R., Zhang, Yana, Chen, Siqi, Li, Zhongmei, Woo, Jonathan M., Ho, Josephine, Vogel, Ian A., Prator, Grace Y., Zhang, Bin, Lee, Youjin, Sun, Zhaolin, Ifergan, Igal, Van Gool, Frédéric, Hargreaves, Diana C., Bluestone, Jeffrey A., Marson, Alexander, and Fang, Deyu
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- 2020
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25. Altered cofactor regulation with disease-associated p97/VCP mutations
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Zhang, Xiaoyi, Gui, Lin, Zhang, Xiaoyan, Bulfer, Stacie L, Sanghez, Valentina, Wong, Daniel E, Lee, YouJin, Lehmann, Lynn, Lee, James Siho, Shih, Pei-Yin, Lin, Henry J, Iacovino, Michelina, Weihl, Conrad C, Arkin, Michelle R, Wang, Yanzhuang, and Chou, Tsui-Fen
- Subjects
Neurodegenerative ,2.1 Biological and endogenous factors ,Aetiology ,Adaptor Proteins ,Signal Transducing ,Adenosine Triphosphatases ,Adenosine Triphosphate ,Autophagy ,Bone Diseases ,Cell Cycle Proteins ,Cell Line ,Tumor ,Chromatography ,Gel ,Golgi Apparatus ,Homeostasis ,Humans ,Muscular Diseases ,Mutation ,Neurodegenerative Diseases ,Phenotype ,Protein Structure ,Tertiary ,Surface Plasmon Resonance ,Valosin Containing Protein ,AAA ATPase ,p97/VCP ,MSP1 ,p47 ,steady-state kinetics - Abstract
Dominant mutations in p97/VCP (valosin-containing protein) cause a rare multisystem degenerative disease with varied phenotypes that include inclusion body myopathy, Paget's disease of bone, frontotemporal dementia, and amyotrophic lateral sclerosis. p97 disease mutants have altered N-domain conformations, elevated ATPase activity, and altered cofactor association. We have now discovered a previously unidentified disease-relevant functional property of p97 by identifying how the cofactors p37 and p47 regulate p97 ATPase activity. We define p37 as, to our knowledge, the first known p97-activating cofactor, which enhances the catalytic efficiency (kcat/Km) of p97 by 11-fold. Whereas both p37 and p47 decrease the Km of ATP in p97, p37 increases the kcat of p97. In contrast, regulation by p47 is biphasic, with decreased kcat at low levels but increased kcat at higher levels. By deleting a region of p47 that lacks homology to p37 (amino acids 69-92), we changed p47 from an inhibitory cofactor to an activating cofactor, similar to p37. Our data suggest that cofactors regulate p97 ATPase activity by binding to the N domain. Induced conformation changes affect ADP/ATP binding at the D1 domain, which in turn controls ATPase cycling. Most importantly, we found that the D2 domain of disease mutants failed to be activated by p37 or p47. Our results show that cofactors play a critical role in controlling p97 ATPase activity, and suggest that lack of cofactor-regulated communication may contribute to p97-associated disease pathogenesis.
- Published
- 2015
26. Calculating risk and prevalence ratios and differences in R: Developing intuition with a hands-on tutorial and code
- Author
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Yorlets, Rachel R., Lee, Youjin, and Gantenberg, Jason R.
- Published
- 2024
- Full Text
- View/download PDF
27. Imaging Thermally Fluctuating Néel Vectors in van der Waals Antiferromagnet NiPS3.
- Author
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Lee, Youjin, Kim, Chaebin, Son, Suhan, Cui, Jingyuan, Park, Giung, Zhang, Kai-Xuan, Oh, Siwon, Cheong, Hyeonsik, Kleibert, Armin, and Park, Je-Geun
- Published
- 2024
- Full Text
- View/download PDF
28. Snowflake relocated Cu2O electrocatalyst on an Ag backbone template for the production of liquid C2+ chemicals from CO2.
- Author
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Lee, Youjin, Choi, Minjun, Bae, Sooan, Tayal, Akhil, Seo, Okkyun, Lim, Hojoon, Lee, Kug-Seung, Jang, Jae Hyuck, Jeong, Beomgyun, and Lee, Jaeyoung
- Subjects
- *
ACETALDEHYDE , *SNOWFLAKES , *BIMETALLIC catalysts , *CUPROUS oxide , *COPPER , *COUPLING reactions (Chemistry) , *LIQUIDS , *SPINE - Abstract
In this study, we performed the CO2 reduction reaction (CO2RR) using a structural composite catalyst of cuprous oxide (Cu2O) and silver (Ag) that was simultaneously electrodeposited. While the underneath Ag electrodeposits maintained their spiky backbone structures even after the CO2RR, the Cu2O deposits were reduced to Cu(111) and relocated on the backbone template. The structural changes in Cu2O to Cu increase the active area of the Cu–Ag interface, resulting in a remarkable production rate of 125.01 μmol h−1 of liquid C2+ chemicals via the stabilization of the C–C coupling of the key intermediate species of acetaldehyde. This study provides new insights into designing a bimetallic catalyst for producing sustainable C2+ products from CO2 without any selectivity towards the production of methane. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
29. Snowflake relocated Cu2O electrocatalyst on an Ag backbone template for the production of liquid C2+ chemicals from CO2.
- Author
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Lee, Youjin, Choi, Minjun, Bae, Sooan, Tayal, Akhil, Seo, Okkyun, Lim, Hojoon, Lee, Kug-Seung, Jang, Jae Hyuck, Jeong, Beomgyun, and Lee, Jaeyoung
- Subjects
ACETALDEHYDE ,SNOWFLAKES ,BIMETALLIC catalysts ,CUPROUS oxide ,COPPER ,COUPLING reactions (Chemistry) ,LIQUIDS ,SPINE - Abstract
In this study, we performed the CO
2 reduction reaction (CO2 RR) using a structural composite catalyst of cuprous oxide (Cu2 O) and silver (Ag) that was simultaneously electrodeposited. While the underneath Ag electrodeposits maintained their spiky backbone structures even after the CO2 RR, the Cu2 O deposits were reduced to Cu(111) and relocated on the backbone template. The structural changes in Cu2 O to Cu increase the active area of the Cu–Ag interface, resulting in a remarkable production rate of 125.01 μmol h−1 of liquid C2+ chemicals via the stabilization of the C–C coupling of the key intermediate species of acetaldehyde. This study provides new insights into designing a bimetallic catalyst for producing sustainable C2+ products from CO2 without any selectivity towards the production of methane. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
30. Ultraviolet light scattering by a silicon Bethe hole.
- Author
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Lee, Dukhyung, Lee, Youjin, and Kim, Dai-Sik
- Subjects
ULTRAVIOLET radiation ,LIGHT scattering ,MAGNETIC dipoles ,ELECTRICAL conductors ,SILICON - Abstract
Bethe's theory predicts that scattering by a small hole on a thin perfect electric conductor (PEC) is presented as radiation by an in-plane magnetic dipole of the incident magnetic field direction. Even in the near-infrared range where metals are no more PEC, the magnetic dipole radiation of Bethe holes has been demonstrated. However, such Bethe holes' nature has not been addressed yet in the ultraviolet (UV) range where conductivity of metals becomes severely deteriorated. Meanwhile, UV plasmonics has been elevating its importance in spectroscopy and photochemistry, recognizing silicon (Si) as an alternative plasmonic metal featuring the interband transition in the UV range. In this work, we expanded the Bethe's theory's prediction to the UV range by investigating Si Bethe holes theoretically and experimentally in terms of the scattering pattern and polarization. Simulation results showed that the scattered field distribution resembles that of an in-plane magnetic dipole, and the dipole direction at oblique incidence is roughly given as the incident magnetic field direction with a deviation angle which can be predicted from the Fresnel equations. Simulation with various diameters showed that the magnetic dipole nature maintains with a diameter less than the quarter-wavelength and multipoles becomes noticeable for diameters larger than the half-wavelength. We performed scattering polarization measurement at 69-degree incidence, which confirms the theoretical analysis. The features of Si Bethe holes demonstrated here will be useful for designing UV plasmonic metasurfaces. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. Partnering With Authors to Enhance Reproducibility at JASA.
- Author
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Wrobel, Julia, Hector, Emily C., Crawford, Lorin, McGowan, Lucy D'Agostino, da Silva, Natalia, Goldsmith, Jeff, Hicks, Stephanie, Kane, Michael, Lee, Youjin, Mayrink, Vinicius, Paciorek, Christopher J., Usher, Therri, and Wolfson, Julian
- Subjects
VALIDITY of statistics ,CLUSTERING of particles ,COMMON misconceptions ,OPEN scholarship - Abstract
The article discusses the reproducibility initiative at the Journal of the American Statistical Association (JASA). The initiative aims to address the lack of standardized practices for reproducibility in scientific research. It establishes minimum criteria for the inclusion of code, data, and workflow in research manuscripts and has implemented a new editorial role, the Associate Editor of Reproducibility (AER), to enforce these standards. The article explains the type of reproducibility being addressed, describes the steps of the review process, and provides guidelines for authors to streamline their reproducibility materials. The JASA reproducibility initiative is part of a larger movement in the scientific community to address the replicability crisis in science. The article emphasizes the importance of reproducibility in statistics to support the validity of research and foster transparency and accountability. It also addresses common questions and misconceptions about the reproducibility review process at JASA. The article concludes by encouraging wider discussions and the adoption of common standards for reproducibility in statistical journals. [Extracted from the article]
- Published
- 2024
- Full Text
- View/download PDF
32. Egg microneedles for transdermal vaccination of inactivated influenza virus.
- Author
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Kang, Geonwoo, Kim, Minkyung, Lee, Youjin, Yang, Huisuk, Seong, Baik-Lin, and Jung, Hyungil
- Published
- 2024
- Full Text
- View/download PDF
33. Finding influential subjects in a network using a causal framework.
- Author
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Lee, Youjin, Buchanan, Ashley L., Ogburn, Elizabeth L., Friedman, Samuel R., Halloran, M. Elizabeth, Katenka, Natallia V., Wu, Jing, and Nikolopoulos, Georgios K.
- Subjects
- *
INFECTIOUS disease transmission , *RESEARCH personnel - Abstract
Researchers across a wide array of disciplines are interested in finding the most influential subjects in a network. In a network setting, intervention effects and health outcomes can spill over from one node to another through network ties, and influential subjects are expected to have a greater impact than others. For this reason, network research in public health has attempted to maximize health and behavioral changes by intervening on a subset of influential subjects. Although influence is often defined only implicitly in most of the literature, the operative notion of influence is inherently causal in many cases: influential subjects are those we should intervene on to achieve the greatest overall effect across the entire network. In this work, we define a causal notion of influence using potential outcomes. We review existing influence measures, such as node centrality, that largely rely on the particular features of the network structure and/or on certain diffusion models that predict the pattern of information or diseases spreads through network ties. We provide simulation studies to demonstrate when popular centrality measures can agree with our causal measure of influence. As an illustrative example, we apply several popular centrality measures to the HIV risk network in the Transmission Reduction Intervention Project and demonstrate the assumptions under which each centrality can represent the causal influence of each participant in the study. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
34. TIA1 variant drives myodegeneration in multisystem proteinopathy with SQSTM1 mutations
- Author
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Lee, YouJin, Jonson, Per Harald, Sarparanta, Jaakko, Palmio, Johanna, Sarkar, Mohona, Vihola, Anna, Evila, Anni, Suominen, Tiina, Penttila, Sini, Savarese, Marco, Johari, Mridul, Minot, Marie-Christine, Hilton-Jones, David, Maddison, Paul, Chinnery, Patrick, Reimann, Jens, Kornblum, Cornelia, Kraya, Torsten, Zierz, Stephan, Sue, Carolyn, Goebel, Hans, Azfer, Asim, Ralston, Stuart H., Hackman, Peter, Bucelli, Robert C., Taylor, J. Paul, Weihl, Conrad C., and Udd, Bjarne
- Subjects
Ubiquitin -- Physiological aspects -- Health aspects ,Autophagy (Cytology) -- Genetic aspects -- Health aspects ,Neurodegenerative diseases -- Development and progression ,Binding proteins -- Health aspects ,Health care industry - Abstract
Multisystem proteinopathy (MSP) involves disturbances of stress granule (SG) dynamics and autophagic protein degradation that underlie the pathogenesis of a spectrum of degenerative diseases that affect muscle, brain, and bone. Specifically, identical mutations in the autophagic adaptor SQSTM1 can cause varied penetrance of 4 distinct phenotypes: amyotrophic lateral sclerosis (ALS), frontotemporal dementia, Paget's disease of the bone, and distal myopathy. It has been hypothesized that clinical pleiotropy relates to additional genetic determinants, but thus far, evidence has been lacking. Here, we provide evidence that a TIA1 (p.N357S) variant dictates a myodegenerative phenotype when inherited, along with a pathogenic SQSTM1 mutation. Experimentally, the TIA1-N357S variant significantly enhances liquid-liquid-phase separation in vitro and impairs SG dynamics in living cells. Depletion of SQSTM1 or the introduction of a mutant version of SQSTM1 similarly impairs SG dynamics. TIA1-N357S-persistent SGs have increased association with SQSTM1, accumulation of ubiquitin conjugates, and additional aggregated proteins. Synergistic expression of the TIA1-N357S variant and a SQSTM1-A390X mutation in myoblasts leads to impaired SG clearance and myotoxicity relative to control myoblasts. These findings demonstrate a pathogenic connection between SG homeostasis and ubiquitin-mediated autophagic degradation that drives the penetrance of an MSP phenotype., Introduction Pathogenic mutations in some genes lead to a spectrum of variably penetrant phenotypes that span different organs and postmitotic tissue (1-4). For example, the same mutation in the autophagic [...]
- Published
- 2018
- Full Text
- View/download PDF
35. Calculating risk and prevalence ratios and differences in R: developing intuition with a hands-on tutorial and code
- Author
-
Yorlets, Rachel R., Lee, Youjin, and Gantenberg, Jason R.
- Published
- 2023
- Full Text
- View/download PDF
36. Single-Cell Genomics Unveils Critical Regulators of Th17 Cell Pathogenicity
- Author
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Gaublomme, Jellert T., Yosef, Nir, Lee, Youjin, Gertner, Rona S., Yang, Li V., Wu, Chuan, Pandolfi, Pier Paolo, Mak, Tak, Satija, Rahul, Shalek, Alex K., Kuchroo, Vijay K., Park, Hongkun, and Regev, Aviv
- Published
- 2015
- Full Text
- View/download PDF
37. CD5L/AIM Regulates Lipid Biosynthesis and Restrains Th17 Cell Pathogenicity
- Author
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Wang, Chao, Yosef, Nir, Gaublomme, Jellert, Wu, Chuan, Lee, Youjin, Clish, Clary B., Kaminski, Jim, Xiao, Sheng, Zu Horste, Gerd Meyer, Pawlak, Mathias, Kishi, Yasuhiro, Joller, Nicole, Karwacz, Katarzyna, Zhu, Chen, Ordovas-Montanes, Maria, Madi, Asaf, Wortman, Ivo, Miyazaki, Toru, Sobel, Raymond A., Park, Hongkun, Regev, Aviv, and Kuchroo, Vijay K.
- Published
- 2015
- Full Text
- View/download PDF
38. Enhanced terahertz conductivity in ultra-thin gold film deposited onto (3-mercaptopropyl) trimethoxysilane (MPTMS)-coated Si substrates
- Author
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Lee, Youjin, Kim, Dasom, Jeong, Jeeyoon, Kim, Jugyoung, Shmid, Volodymyr, Korotchenkov, Oleg, Vasa, Parinda, Bahk, Young-Mi, and Kim, Dai-Sik
- Published
- 2019
- Full Text
- View/download PDF
39. Strain-Enabled Local Phase Control in Layered MoTe2 for Enhanced Electrocatalytic Hydrogen Evolution.
- Author
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Lee, Youjin, Lee, Soo Hyun, Han, Sun Kyung, Park, Jiheon, Lee, Dongwook, Preston, Daniel J., Kim, In Soo, Hersam, Mark C., Kwon, Yongwoo, Shong, Bonggeun, and Lee, Won-Kyu
- Published
- 2023
- Full Text
- View/download PDF
40. Participation of the unstable lattice oxygen of cation-exchanged δ-MnO2 in the water oxidation reaction.
- Author
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Ham, Kahyun, Kang, Sinwoo, Kim, Yeongin, Lee, Youjin, Kim, Young-Dok, and Lee, Jaeyoung
- Abstract
Among 3d transition metal oxides, Mn oxides function as electrocatalysts for the oxygen evolution reaction (OER) in alkaline media. At the OER potential, some Mn oxides are oxidized to a layered structure birnessite-type δ-MnO
2 , so strategies to improve the OER activity of δ-MnO2 and elucidate its reaction mechanism have been suggested. Here, we demonstrated for the first time that δ-MnO2 can follow the lattice oxygen participation mechanism (LOM) rather than the conventional adsorbate evolution mechanism and the contribution of LOM can improve the OER activities of δ-MnO2 . Consistent with the electrochemical evidence for LOM, we found the isotopic shift of Mn–O and active oxygen in an18 O-labeling experiment by in situ Raman analysis. The oxygen vacancies introduced by the intercalated cation between MnO6 layers thermodynamically activate the lattice oxygen of δ-MnO2 and absorb OH− ions in the alkaline electrolyte, enabling the unstable lattice oxygen to participate in the OER as the reactant. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
41. Targeted sequencing and identification of genetic variants in sporadic inclusion body myositis
- Author
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Weihl, Conrad C., Baloh, Robert H., Lee, Youjin, Chou, Tsui-Fen, Pittman, Sara K., Lopate, Glenn, Allred, Peggy, Jockel-Balsarotti, Jennifer, Pestronk, Alan, and Harms, Matthew B.
- Published
- 2015
- Full Text
- View/download PDF
42. Corrigendum to “Calculating risk and prevalence ratios and differences in R: Developing intuition with a hands-on tutorial and code” [Ann Epidemiol 86 (2023) 104–109]
- Author
-
Yorlets, Rachel R., Lee, Youjin, and Gantenberg, Jason R.
- Published
- 2024
- Full Text
- View/download PDF
43. Observation of plateau-like magnetoresistance in twisted Fe3GeTe2/Fe3GeTe2 junction.
- Author
-
Kim, Junghyun, Son, Suhan, Coak, Matthew J., Hwang, Inho, Lee, Youjin, Zhang, Kaixuan, and Park, Je-Geun
- Subjects
MAGNETORESISTANCE ,MAGNETIC materials ,TUNNEL magnetoresistance ,GIANT magnetoresistance ,SYMMETRY breaking ,TUNNEL junctions (Materials science) - Abstract
Controlling the stacking of van der Waals (vdW) materials is found to produce exciting new findings, since hetero- or homo-structures have added the diverse possibility of assembly and manipulated functionalities. However, so far, the homostructure with a twisted angle based on the magnetic vdW materials remains unexplored. Here, we achieved a twisted magnetic vdW Fe
3 GeTe2 (FGT)/Fe3 GeTe2 junction with broken crystalline symmetry. A clean and metallic vdW junction is evidenced by the temperature-dependent resistance and the linear I–V curve. Unlike the pristine FGT, a plateau-like magnetoresistance (PMR) is observed in the magnetotransport of our homojunction due to the antiparallel magnetic configurations of the two FGT layers. The PMR ratio is found to be ∼0.05% and gets monotonically enhanced as temperature decreases like a metallic giant magnetoresistance. Such a tiny PMR ratio is at least three orders of magnitude smaller than the tunneling magnetoresistance ratio, justifying our clean metallic junction without a spacer. Our findings demonstrate the feasibility of the controllable homostructure and shed light on future spintronics using magnetic vdW materials. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
44. Metallothioneins negatively regulate IL-27-induced type 1 regulatory T-cell differentiation
- Author
-
Wu, Chuan, Pot, Caroline, Apetoh, Lionel, Thalhamer, Theresa, Zhu, Bing, Murugaiyan, Gopal, Xiao, Sheng, Lee, Youjin, Rangachari, Manu, Yosef, Nir, and Kuchroo, Vijay K.
- Published
- 2013
45. IL-21R signaling is critical for induction of spontaneous experimental autoimmune encephalomyelitis
- Author
-
Lee, Youjin, Mitsdoerffer, Meike, Xiao, Sheng, Gu, Guangxiang, Sobel, Raymond A., and Kuchroo, Vijay K.
- Subjects
Gene expression -- Health aspects ,Interleukins -- Health aspects ,Encephalomyelitis -- Genetic aspects -- Development and progression ,Autoimmune diseases -- Genetic aspects -- Development and progression ,Health care industry - Abstract
IL-17-producing [CD4.sup.+] T cells (Th17 cells) have well-described pathogenic roles In tissue Inflammation and autoimmune diseases, such as experimental autoimmune encephalomyelitis (EAE); however, the involvement of IL-21 in these processes has remained controversial. While IL-21 is an essential autocrine amplification factor for differentiation of Th17 cells, the loss of IL-21 or IL-21 receptor (IL-21R) does not protect mice from actively induced EAE. Here, we utilized a transgenic EAE mouse model, in which T and B cells overexpress receptors for myelin oligodendrocyte glycoprotein (MOG) (referred to as 2D2xTH mice), and demonstrated that IL-21 is critical for the development of a variant form of spontaneous EAE in these animals. Il21r deletion in 2D2xTH mice reduced the incidence and severity of spontaneous EAE, which was associated with a defect in Th17 cell generation. Moreover, IL-21R deficiency limited IL-23R expression on Th17 cells and inhibited expression of key molecules involved in the generation of pathogenic Th17 cells. Conversely, loss of IL-23R in 2D2xTH mice resulted in complete resistance to the development of spontaneous EAE. Our data identify a previously unappreciated role for IL-21 in EAE and reveal that IL-21-mediated signaling supports generation and stabilization of pathogenic Th17 cells and development of spontaneous autoimmunity., Introduction Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) that is thought to be driven by pathogenic [CD4.sup.+] Th cells (1, 2). Experimental autoimmune [...]
- Published
- 2015
- Full Text
- View/download PDF
46. Terahertz Spectroscopy and DFT Analysis of Phonon Dynamics of the Layered Van der Waals Semiconductor Nb3X8 (X = Cl, I).
- Author
-
Kim, Jangwon, Lee, Youjin, Choi, Young Woo, Jung, Taek Sun, Son, Suhan, Kim, Jonghyeon, Choi, Hyoung Joon, Park, Je-Geun, and Kim, Jae Hoon
- Published
- 2023
- Full Text
- View/download PDF
47. Doubly robust nonparametric instrumental variable estimators for survival outcomes.
- Author
-
Lee, Youjin, Kennedy, Edward H, and Mitra, Nandita
- Subjects
- *
SURVIVAL rate , *INSTRUMENTAL variables (Statistics) , *NONPARAMETRIC estimation , *CAUSAL inference , *EARLY detection of cancer , *OVARIAN cancer , *MACHINE learning - Abstract
Instrumental variable (IV) methods allow us the opportunity to address unmeasured confounding in causal inference. However, most IV methods are only applicable to discrete or continuous outcomes with very few IV methods for censored survival outcomes. In this article, we propose nonparametric estimators for the local average treatment effect on survival probabilities under both covariate-dependent and outcome-dependent censoring. We provide an efficient influence function-based estimator and a simple estimation procedure when the IV is either binary or continuous. The proposed estimators possess double-robustness properties and can easily incorporate nonparametric estimation using machine learning tools. In simulation studies, we demonstrate the flexibility and double robustness of our proposed estimators under various plausible scenarios. We apply our method to the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial for estimating the causal effect of screening on survival probabilities and investigate the causal contrasts between the two interventions under different censoring assumptions. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
48. Proinflammatory T helper type 17 cells are effective B-cell helpers
- Author
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Mitsdoerffer, Meike, Lee, Youjin, Jäger, Anneli, Kim, Hye-Jung, Korn, Thomas, Kolls, Jay K., Cantor, Harvey, Bettelli, Estelle, and Kuchroo, Vijay K.
- Published
- 2010
49. Unexpected Targets and Triggers of Autoimmunity
- Author
-
Lee, Youjin, Collins, Mary, and Kuchroo, Vijay K.
- Published
- 2014
- Full Text
- View/download PDF
50. An Expandable Yield Prediction Framework Using Explainable Artificial Intelligence for Semiconductor Manufacturing.
- Author
-
Lee, Youjin and Roh, Yonghan
- Subjects
SEMICONDUCTOR manufacturing ,ARTIFICIAL intelligence ,STANDARD deviations ,SEMICONDUCTOR devices ,SEMICONDUCTOR industry ,PRODUCTION management (Manufacturing) - Abstract
Enormous amounts of data are generated and analyzed in the latest semiconductor industry. Established yield prediction studies have dealt with one type of data or a dataset from one procedure. However, semiconductor device fabrication comprises hundreds of processes, and various factors affect device yields. This challenge is addressed in this study by using an expandable input data-based framework to include divergent factors in the prediction and by adapting explainable artificial intelligence (XAI), which utilizes model interpretation to modify fabrication conditions. After preprocessing the data, the procedure of optimizing and comparing several machine learning models is followed to select the best performing model for the dataset, which is a random forest (RF) regression with a root mean square error (RMSE) value of 0.648. The prediction results enhance production management, and the explanations of the model deepen the understanding of yield-related factors with Shapley additive explanation (SHAP) values. This work provides evidence with an empirical case study of device production data. The framework improves prediction accuracy, and the relationships between yield and features are illustrated with the SHAP value. The proposed approach can potentially analyze expandable fields of fabrication conditions to interpret multifaceted semiconductor manufacturing. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
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